proceeding in this or any foreign country, shall be given in evidence, or in any manner used against him or his property or estate, in any court of the United States, in any criminal proceeding, or for the enforcement of any penalty or forfeiture; provided that this section shall not exempt any party or witness from prosecution and punishment for perjury committed in discovering or testifying as aforesaid." 25 This does not deprive a witness of the right to refuse to give testimony that might tend to criminate him." The Revised Statutes further provide that: "No testimony given by a witness before either House, or before any committee of either House of Congress, shall be used as evidence in any criminal proceeding against him in any court, except in a prosecution for perjury committed in giving such testimony. But an official paper or record produced by him is not within the said privilege." "No witness is privileged to refuse to testify to any fact, or to produce any paper, respecting which he shall be examined by either House of Congress, or by any committee of either House, upon the ground that his testimony to such fact or his production of such paper may tend to disgrace him or otherwise render him infamous." 28 The rules regulating the production of documents by a subpœna duces tecum or otherwise have been previously explained.29 25 U. S. R. S., § 860. 26 Counselman v. Hitchcock, 142 U. S. 547; U. S. v. James, 60 Fed. R. 257. See Brown v. Walker, 161 U. S. 591; Ex parte Irvine, 74 Fed. R. 954; U. S. v. Price, 96 Fed. R. 960. A witness, at least if not a party to the suit, may be compelled to testify as to an infringement of a patent himself, when relevant, and is not shielded by the Constitution because he may thereby prove his own liability to treble damages. Masseth v. Johnston, 59 Fed. R. 613. A defendant when called by the complainant as a witness may be compelled to state whether he has in his possession a machine claimed to be an infringement of the plaintiff's patent, although the plaintiff has not previously made out a prima facie case of infringement. Delamater v. Reinhardt, 43 Fed. R. 76, S. D. N. Y. Contra, Celluloid Co. v. Crane Co., 3d 29 Supra, § 267. It was held that a witness compelled to testify before a pension examiner without notice or knowledge of his constitutional privilege cannot be indicted for perjury thereupon. U. S. v. Bell, 81 Fed. R. 830. § 275. Subpoenas ad testificandum.- The attendance of a witness is usually compelled in equity as in law by the service of a subpoena ad testificandum, and the payment of his fees and mileage. A subpoena ad testificandum is substantially in the same form in equity as in law. When issued from a court of the United States, it must be under the seal of the court, and signed by the clerk; and is usually also signed by the solicitors of the party at whose request it issues. Those issued from the Supreme Court or a Circuit Court must bear teste from the day of such issue of the Chief Justice of the United States, or, when that office is vacant, of the associate justice next in precedence.2 Those issuing from a District Court must bear teste of the judge, or, when that office is vacant, of the clerk thereof. By the common law, the names of but four witnesses could be included in one subpoena. The Revised Statutes, however, provide that, "to save unnecessary expense, it shall be the duty of the clerk to insert the names of as many witnesses in a cause in such subpoena as convenience in serving the same will permit." If the witness can be served within the jurisdiction of the court where the suit is pending, or within a hundred miles of the place of holding that court, the subpoena may be issued from its clerk's office. If he cannot, and it is desired to take his testimony de bene esse under the acts of Congress,' application for the issue of the subpoena must be made to the court of the district in which the examination is to be made. It has been held that Congress has no power to authorize or compel the courts of the United States to issue subpoenas or punish for contempt witnesses before a Congressional Commission, such as the Pacific Railway Commission, or the Interstate Commerce Commission,10 or an executive officer." "Witnesses 275. 1 For the amount of his fees etts, 1 Cranch, C. C. 580; Ex parte and mileage, see § 333. Peck, 3 Blatchf. 113. See infra, § 276. 2 U. S. R. S., §§ 911, 912. 3 U. S. R. S., §§ 911, 912. 4 Erwin v. U. S., 37 Fed. R. 470, 490. 5 U. S. R. S., § 829; Erwin v. U. S., 37 Fed. R. 470, 490. 6 U. S. R. S., § 876. 8 U. S. R. S., § 863; U. S. v. Tilden, 25 Int. Rev. R. 352; Ex parte Humphrey, 2 Blatch. 228; Henry v. Rick 9 In re Pac. Ry. Com., 32 Fed. R. 241. 10 In re Interstate Commerce Commission, 53 Fed. R. 476. 11 In re McLean, 37 Fed. R. 648. Cf. U. S. R. S., § 4906; Ex parte Moses, 53 Fed. R. 346. General courtsmartial are authorized by statute to issue subpoenas to witnesses within the judicial district. 31 St. at L. who are required to attend any term of a Circuit or District Court on the part of the United States, shall be subpoenaed to attend to testify generally on their behalf, and not to depart the court without leave thereof, or of the district attorney; and under such process they shall appear before the grand or petit jury, or both, as they may be required by the court or district attorney." 12 It has been held that a witness cannot be compelled by subpoena to produce the patterns of the castings of a stove, which are in his possession.13 276. Service of a subpoena ad testificandum.- A subpœna to appear and testify may be served by the marshal of the court, or by any other person acting as the agent of the party calling the witness. The Revised Statutes provide that "subpoenas for witnesses who are required to attend a court of the United States, in any district, may run into any other district; provided, that in civil causes the witnesses living out of the district in which the court is held do not live at a greater distance than one hundred miles from the place of holding the same." A witness' attendance at a court more than one hundred miles from the place where he lives cannot be compelled by the service of a subpoena upon him within the district, when he has been enticed there by false pretenses; or while there to attend either as a party, a witness, an attorney, or a counsel during a suit or other judicial proceeding in a State or Federal court; or, while traveling upon his way to or from Congress, if he be a member thereof; or if there in the course of the performance of any public duty.7 5 2 U. S. R. S., § 876; Ex parte Beebee, 2 Wall. Jr. 127; Henry v. Ricketts, 1 Cranch, C. C. 580; U. S. v. Williams, 4 Cranch, C. C. 372. 3 Union S. R. Co. v. Mathiesson, 2 Cliff. 304; Steiger v. Bonn, 4 Fed. R. 17. 4 Juneau Bank v. M'Spedan, 5 Biss. 64; Matthews v. Tufts, 87 N. Y. 568. But see Blight v. Fisher, Pet. C. C. 41. 5 Parker v. Hotchkiss, 1 Wall. Jr. 269; Matthews v. Tufts, 87 N. Y. 568. Contra, Blight v. Fisher, Pet. C. C. 41. 6 Const., art. I, § 6; Miner v. Markham, 28 Fed. R. 387. 7 See § 98. "When a commission has been issued by any court of the United States for taking the testimony of a witness named therein at any place within any district or Territory, the clerk of any court of the United States for such district or Territory shall, on the application of either party to the suit, or of his agent, issue a subpoena for such witness, commanding him to appear and testify before the commissioner named in the commission, at any time and place stated in the subpoena; and if any witness, after being duly served with subpoena, refuses or neglects to appear, or, after appearing, refuses to testify, not being privileged from giving testimony, and such refusal or neglect is proven to the satisfaction of any judge of the court whose clerk issues such subpoena, such judge may proceed to enforce obedience to the process, or punish the disobedience, as any court of the United States may proceed in case of disobedience to process of subpoena to testify issued by such court." 8 "When either party in such suit applies to any judge of a United States court in such district or Territory for a subpoena commanding the witness, therein to be named, to appear and testify before said commissioner, at the time and place to be stated in the subpoena, and to bring with him and produce to such commissioner any paper or writing or written instrument or book or other document supposed to be in the possession or power of such witness, and to be described in the subpoena, such judge, on being satisfied, by the affidavit of the person applying, or otherwise, that there is reason to believe that such paper, writing, written instrument, book, or other document is in the possession or power of the witness, and that the same, if produced, would be competent and material evidence for the party applying therefor, may order the clerk of said court to issue such subpoena accordingly. And if the witness, after being served with such subpoena, fails to produce to the commissioner, at the time and place stated in the subpoena, any such paper, writing, written instrument, book, or other document, being in his possession or power, and described in the subpoena, and such failure is proved to the satisfaction of said judge, he may proceed to enforce obedience to said process of subpoena, or punish the disobedience, in like manner as any 8 U. S. R. S., § 868. court of the United States may proceed in case of disobedience to like process issued by such court. When any such paper, writing, written instrument, book, or other document is produced to such commissioner, he shall, at the cost of the party requiring the same, cause to be made a correct copy thereof, or of so much thereof as shall be required by either of the parties."9 "No witness shall be required, under the provisions of either of the two preceding sections, to attend at any place out of the county where he resides, nor more than forty miles from the place of his residence, to give his deposition; nor shall any witness be deemed guilty of contempt for disobeying any subpoena directed to him by virtue of either of the said sections, unless his fee for going to, returning from, and one day's attendance at the place of examination are paid or tendered to him at the time of the service of the subpoena." 10 9 U. S. R. S., § 869. 10 U. S. R. S., § 870. U. S. R. S., § 871. "When a commission to take the testimony of any witness found within the District of Columbia, to be used in a suit depending in any State or Territorial or foreign court, is issued from such court, or a notice to the same effect is given according to its rules of practice, and such commission or notice is produced to a justice of the Supreme Court of said District, and due proof is made to him that the testimony of such witness is material to the party desiring the same, the said justice shall issue a summons to the witness, requiring him to appear before the commissioners named in the commission or notice, to testify in such suit, at a time and at a place within said District therein specified." U. S. R. S., § 872. "When it satisfactorily appears by affidavit to any justice of the Supreme Court of the District of Columbia, or to any commissioner for taking depositions appointed by said court: first, that any person within said District is a ma terial witness for either party in a suit pending in any State or Territorial or foreign court; second, that no commission nor notice to take the testimony of such witness has been issued or given; and, third, that, according to the practice of the court in which the suit is pending, the deposition of a witness taken without the presence and consent of both parties will be received on the trial or hearing thereof,- such officer shall issue his summons, requiring the witness to appear before him at a place within the District, at some reasonable time, to be stated therein, to testify in such suit." U. S. R. S., § 873. "Testimony obtained under the two preceding sections shall be taken down in writing by the officer before whom the witness appears, and shall be certified and transmitted by him to the court in which the suit is pending, in such manner as the practice of that court may require. If any person refuses or neglects to appear at the time and place mentioned in the summons, or, on his appearance, refuses to testify, he shall be liable to the |